Other products like canned soup and stock contained too much animal product, according to the body.

Mr Badger said he had heard CFIA was conducting a health-risk assessment to see whether the ruling could be overturned.

Iconic: Marmite is a British staple, but it is one of several foods banned in a letter to a Canadian shop owner

He said: 'When this health-risk assessment is done we should know definitively whether you can import Irn-Bru.'

A spokesman for A.G. Barr, which makes Irn-Bru, said the company produces a Canada-specific product in a specially-labelled 500ml plastic bottle which does not contain Ponceau 4R, and has been exporting via a local distributor for more than 15 years.

It is the only Irn Bru product A.G. Barr exports to Canada, according to the spokesman.

But Mr Badger said to his knowledge, all British specialty shops in Canada were selling the British recipe.

Canada is home to one of the largest populations of Scottish expats.

The CFIA has yet to comment.

Irn-Bru maker A.G. Barr’s website said the company was working to replace the food colouring to bring it in line with guidelines set by the UK’s Food Standards Agency. However, the company assured the public the colouring is safe.